The host to which the ICMP echo request is to be sent,
the ping time between the host identified by this index
object and the agent's host is what is queried for, see
description of icmpEchoReqTable for more details.
The object serves as the last index out of three indices
used when the object icmpEchoReqTime is queried. Note that
this object's value cannot be queried for, this object serves
as an input to the agent itself and a query for this object
makes no sense.